Switch actuating assembly



F 1, 1954 K. DAUGIRDAS ETAL 3,

SWITCH ACTUATING ASSEMBLY 3 Sheets-Sheet 2 F I63 Flled May 5, 1960 F IG .2

V EN TORS.

SHMUEL BERL/NSKY A T TORNEYB' Feb. 11, 1964 DAUGlRDAs ETAL 3,121,152

SWITCH ACTUATING ASSEMBLY Filed May 5, 1960 '3 Sheets-Sheet 3 FIG. 8 m2 352 FIG. 9 66 l 2:

Z 72' INVENTORS. 1 SHNl/EL BERL/NSKY 82 68 mun/PA; DAUG/RDAS ATTORNEYS United rates Patent Ollice 3,l2l,l52 Patented Feb. 11, 1954:

The present invention relates to mechanism adapted to be manually operated and to actuate a switch or the like in accordance with the manual operation thereof. It is specifically designed for controlling the operation of motors adapted to open and close the doors on public transportation vehicles such as buses, but in its broader aspects it is applicable to other uses as well.

Treadle control of devices such as the doors of public transportation vehicles has obvious advantages, largely revolving about the fact that the mere presence of an individual in a given location (on the treadle) will cause the doors to be opened without requiring any special action on the part of that individual. Nevertheless treadles have serious drawbacks, arising primarily from diilicu ties of maintenance and susceptibility to damage. Treadles are necessarily located on the floor and therefore are subject to attack by accumulations of water, dirt or the like. Moreover, excessive pressure concentrations suc as accompanying the use of high heels or crutches often tend to tear or distort operating parts of the treadle.

it has been found that initial cost is greatly lessened and, which is much more important, breakdowns and maintenance problems are greatly decreased, if control of the door operating motor is achieved by means of a device mounted off the floor and preferably on the door. That such a device must be manipulated manually is a disadvantage which is considered acceptable. Many types of such devices have been proposed in the past, e.g., door-carried handles, rods, plates and bars. They have an general been characterized by the fact that they are normally spring urged to a given position and can be manually moved in but a single direction in order to actuate a switch and cause the door operator to open the door. in some instances that single direction is toward the person who is manipulating the device, in other instances it is away from him, and sometimes it is in a lateral direction, but whatever the direction, the devic can be efiectively manipulated only in that direction and in no other direction.

This represents a considerable drawback, particularly for public transportation vehicles where passengers are often heavily laden with packages and therefore cannot conveniently manipulate a rod or bar movable only in a given fixed direction. Moreover, with public transportation vehicles it is desirable that passengers be permitted to alight with as little delay as possible, and if a given control system includes a rod which is adapted to be pulled, and the passenger insists upon t ying to push it, considerable time may be lost before the passenger can figure out what he must do in order to gain his freedom from the vehicle. The very variety in the modes of movement characteristic of the many prior art devices now in service necessarily greatly complicates the problem.

It is therefore a prime object of the present invention to devise a switch actuating assembly in which the manually movable member can be moved in any one of a plurality of directions in order to actuate the switch controlled thereby. More specifically, in accordance with the present invention movement of the manually actuatable member or any part thereof horizontally, whether toward or away from the operator, laterally to either side or diagonally, and even tilting or pivotal movement of the manually actuatable member, will all result in switch actuation.

In order to be useful from a practical point of View, it is h ghly desirable that an assembly of this character require the application thereto of some minimal force before the switch is actuated, thus preventing accidental switch actuation in response to vibration or shock. The structure of the present invention has this desirable characteristic. in addition, the parts are reliably held against rattling during movement of the vehicle.

T he parts of the assembly of the present invention may be inexpensively manufactured and do not require any great degree of precision. Their assembly is simple, and when assembled, particularly in the preferred embodiment illustrated in FIGS. 25, they are effectively sealed against deleterious external influences.

in accordance with the above, the device of the present invention com rises a movable touch bar member adapted to be mounted in exposed position on any supporting structure, such as a door or the like, between a pair of members fixed to that supporting structure. The touch bar carries a pair or" connecting elements which are received within sockets formed in the fixed members, the connecting elements being rockable relative to the touch bar and to the sockets in the fixed members in which they are received. The touch bar is spring-loaded to an inoperative position, but may be moved against the action of that spring bias laterally or pivotally relative to the fixed members. In so moving the connecting elements are rocked. A switch is operatively connected to a connecting element and is sensitive to the rocking action thereof, thereby to control the operation of some mechanism, such as a door opening motor or the like, in accordance therewith. it is preferred, as here specifically disclosed, to provide a pair of switches operatively connected respectively to the connecting elements at the upper and lower end of the touch bar, so that the door operating motor will be reliably actuated no matter where along its entire length the touch bar is pushed.

The spring biasing means for locating the touch bar in its normal inoperative position is preferably directly active between one of the connecting elements and a socket in which it is received, the engaging portions of the connecting element and socizet being essentially planar so that when the element is rocked relative to its socket an elongation or ohange in effective longitudinal dimension will result, this occurring in the direction in which the resilient biasing means is active and against the force exerted by that biasing means. In this way a trigger action is produced, the application or" sufiicient force on the touch but to overcome the action of the resilient biasing means be ng equired in order to move the touch bar from its inoperative position and thus actuate the switch controlled thereby.

To accomplishment of the above, and to such other objects as may hereinafter appear, the present invention relates to a switch actuating assembly as defined in the appended claims and as described in this specification, taken together with the accompanying drawings, in which:

FIG. 1 is a schematic and circuit diagram illustrating one way in which the device of the present invention can be used to control a door operating motor in a public transportation vehicle or the like;

PEG. 2 is a side elevational view, partially broken away and cross sectioned, of one embodiment of the present invention, the parts being shown in their normal inoperative position;

FIG. 3 is a view similar to FIG. 2 but showing the parts in their operative switohclosing position;

FIG. 4 is a cross sectional view taken along the line 4-4 of FIG. 2;

FIG. 5 is a front elevational view of the fixed and movable members of the assembly of FIG. 2, ready for application to a mounting plate;

FIG. 6 is a view similar to RS. 3, but in which the touch bar is moved laterally from its normal [position without any pivotal movement relative thereto;

FIG. 7 is a view similar to FIG. 6 but showing a modified structure and mounting of the connecting element which extends between the touch bar and the switch actuated by movement thereof;

FIG. 8 is a low similar to PEG. 2. but of an alternative embodiment; and

FIG. 9 is a view similar to FIG. 5 but of the embodiment of FIG. 8.

The assembly of the present invention is in the form here specifically disclosed, designed to control a motor 2 (see FIG. 1), adapted to open and close the doors 4 of a public transportation vehicle, such as the rear entrance doors thereof. The doors 4 are mounted on shafts 6 which are mechanically connected in any appropriate manner, as indicated by the broken lines 8, with the motor 2', so that the latter can move the doors 4 between open and closed positions. The motor 2. is adapted to be selectively energized to go through a cycle of door-opening and door-closing operations by means of a circuit Whic may be traced from positive terminal it? through a normally open switch 12 and through a drivers control switch 14. As shown in FIG. 1 four switches 12 are employed, two on each of the doors 4, and those switches, or any one of them, are adapted to be actuated to closed position, energizing the motor 2, through movement of a movable member in the form of a touch bar 16, one of which is schematically shown in FIG. 1 on each door 4.

FIGS. 26 illustrate a preienred embodiment for the construction and mounting of the movable touch bar member 16 and of the switches 12 adapted to be actuated thereby. The assembly comprises a pair of fixed housing members '18 and 18a adapted to be secured to a mounting plate 26 in any appropriate manner, as by the screws 22. When, as is here specifically disclosed, the assembly is adapted to be mounted on a door, the mounting plate 2 may'comprise the front surface of that door. A switch 12 is received within each fixed housing member 13, 18a, and in the form here specifically disclosed comprises an insulating bushing 24 received in housin aperture 26 and held in place by screws 23, that bushing 24 having an inwardly projecting flange 353* which carries a conductive ring 32 on the inside thereof which is connected to one of the leads 34 from the switch 12. A helically coiled conductive spring 35 is in physical and electrical engagement with a conductive ring 38 fixed to the upper portion of the bushing 24 and from which switch lead 49' extends, the s ring 36 projecting down through the ring 32 and carrying a contact ring 42 on its periphery inside and normally spaced from the ring 32. The rings 32 and 42 constitute the fixed and movable contacts respectively of the switch 12. The resiliency of the spring 3-5- issu h as to tend to assume the straight configuration shown in FIG. 2, the rings 32 and 42. then being spaced from one another to define an open-circuit switch condition. The spring 36 is, however, dis-tortable against its inherent resiliency to the position shown in PEG. 3, in which position the ring 42 engages the ring 32 to define a closedcircuit switch condition.

The facing surfaces of the upper and lower fixed housing members 18 and 18a respectively are provided with inwardly tapered sockets 4 having substantially planar bottoms with apertures 43 c mmunicating between the sockets and the interior of the housings l3, On the upper fixed member the socket 44' is siuroundei by a depending flange 5h, whereas on the lower fixed member the socket is formed in an upwardly protruding portion 52 having a groove 54- around the periphery thereof.

The movable touch bar member it; comprises a metallic tube 56 which extends between the facing surfaces of the fixed housing members 18 and 33a. The lower end of that tube 55 is closed by a plug 53 having a downwardly extending and radially outward located flange 68- which is received around the upwardly protruding portion 52 of the lower fixed housing member l8. A distortable soft rubber sealing ring 62 is received within the groove 54 on the protruding portion 52 and engages the inner surface of the flange all. The downwardly facing surface of the plug 58 is provided with an inwardly tapered socket as having a substantially planar bottom 65. The upper end of the tube 55 is closed by a plug 6-8 extending. axially beyond the tube as and received inside the flange 5% depending from the upper fixed member 3, a distortable soft rubber sealing ring 7% being received within peripheral groove 72 on the plug 63 and engaging the inner surface of the flange The plug 68 is provided with a central passage 74- within which part 76 is slidab-le, that part 76 having a depending portion '73 of reduced radius which passes through aperture St? in the bottom wall of the plug 68. A spring 82 is compressed within the passage 74 beneath the part 76 and urges that part upwardly. The upper surface of the part 7c is provided with an inwardly tapered socket 8% having a substantially planar bottom 86.

The assembly further comprises a pair of connecting elements generally designated 88, each having a substantially cylindrical body portion fill with essentially planar top and bottom surfaces 92 and 94 respectively, the body portion 96 extending between and being received in each opposed pair of sockets 44, 84 and 44, 64 respectively, the essentially planar upper and lower surfaces 92, 9d of the body portions 99 of the two connecting elements 8% engaging with the correspondingly essentially planar socket bottoms 46, $6 and 46, 66 repectively. Each of the body portions 9% of the connecting elements 88 is provided with an elongated extension part Q6 of reduced diameter which passes freely through the aperture 48 associated with the corresponding socket 44 and extends up into the interior of the switch spring 36 associated therewith. The connecting element 88 is preferably formed of some suitable electrically insulating material such as nylon.

With the parts in their normal position, as shown in PEG. 2, the spring 82 urges the body portion 99 of the upper connecting element 88 into seated position in the sockets 44 and 84 and, by reaction, also urges the body portion 9t) of the lower connecting element 88 into seated position within the sockets 44 and 64. This centers the movable touch bar member 56, maintains it in upright position, and prevents it from rattlin The connecting elements 88 are also in upright position, and the switches 12 are in open-circuit condition. If now the movable touch bar element 56 is moved laterally by the application of pressure thereto in any lateral direction at any point along its length (and by lateral direction is meant a direction having a component of movement in a plane substantiallly perpendicular to the plane of the drawings) the movable touch bar element 56 will either move bodily laterally relative to the fixed sockets 4 as shown in FIG. 6, or else, as shown in FIG. 3, its movement relative to those sockets will be partially lateral and partially pivotal. in either event the body portions 9%} of the connecting portions 83, or at least one of them, will depart from its vertical position shown in FIG. 2 and will assume an inclined position such as that shown in FIGS. 3 and 6, in so doing rocking with respect to the socxet 44- in the fixed housing member 18, and sometimes also rocking with respect to the socket ea or 34 respectively in the movable touch bar member 56. in view of the essentially planar nature of the socket bottoms 46, 66 and and the upper and lower end surfaces 92 and $4- of the connecting element body portions 93, the rocking of the connecting elements 88 will necessarily result in a compression of the spring 82,

the part 76 moving axially inwardly through the passage 74 against the action of the spring 82. Since an appreciable amount of force is required to compress the spring 82, it will be seen that rocking movement of the connecting elements 88, and hence lateral movement of the movable touch bar member 16, can occur only when the pressure applied thereto is sufficient to overcome the pressure exerted by the spring 82.

When the connecting element 88 rocks, the upper end of its extending part 96 is translated laterally over an appreciable distance, and since it is received inside the switch spring 36, that spring is also moved laterally until the ring 42 is brought into engagement with the ring 32, thus closing the switch 12 and, provided that the drivers switch 14 is also closed, actuating the motor 2 to open the doors 4.

When manual pressure is released from the movable touch bar member 16, the spring 32 active on the slideble part 76 causes the various elements of the assembly to resume their normal position shown in PEG. 2, thus opening the switch 12.

The flexible sealing rings 7%} protect the switches 12 and the other parts of the assembly from dust, dirt and moisture. Since all of the parts are mounted on the door, and hence are raised well above the floor, there is little or no likelihood of such as accumulation of water or the like as to require any more eifective seal, but a more positive type of seal could be provided, if desired, as by compressing both the inner and outer edges of the rings 62. and 72 within grooves formed in the encompassing structural parts.

It is not necessary that both of the sockets 44, 64 or 44, 84 in which each body portion 9%} of a connecting element 88 is received have flat or substantially planar bottom walls. For example, FIG. 7 illustrates a modification in which the socket 44 in the fixed housing member 13 has a planar bottom 46, but in which the socket 840: in the sliding plug part 76 is rounded, the lower surface 94a of the body portion 99a of the connecting element 88 being correspondingly rounded. Since the upper surface 92 of the connecting element body portion 99 is flat and cooperates with the fiat bottom surface 46 of the socket 44, the operation of the assembly will be substantially the same as that of FIG. 6. Thus when the touch bar 16 is displaced from its normal position the rocking of the connecting element body portion Etta with respect to the flat bottom surface 46 of the socket 4 2 will tend to force the slidable part 76 downwardly against the action of the spring 92, that spring therefore serving, as in the previously described embodiment, to retain the touch bar in its inoperative position and producing a resilient force against which the touch bar 16 must be moved it the switch 12 is to be actuated. Although in FIG. 7 the rounded socket 84a is shown in the slidable part 76a and the flat-bottomed socket 44 is shown in the fixed housing 18, the relationship could be reversed, with the flat bottom socket in the slidable part 76a and the rounded socket in the fixed housing 18. The term rounded, in connection with the socket, is used generically to relate to a socket which, in conjunction with the surface of the connecting element body part 99 cooperating therewith, does not produce an operative elongation of that portion of the body part 94} which extends between the two sockets in which it is received when the connecting element 88 is rocked.

The alternative embodiment disclosed in FIGS. 8 and 9 operates on the same principle as the embodiment of FIGS. 26 and is essentially structurally similar thereto in many respects. Structural elements in the embodiments of FIGS. 8 and 9 which are similar to the elements in the previously described embodiment are identified by similar reference numerals diiferentiated, however, by being primed.

The embodiment of FIGS. 8 and 9 diiiers from the previously described embodiment primarily in two respects, to wit, the type of switch employed and the relative locations of the fixed and movable members. In the embodiment of FIGS. 8 and 9 the movable touch bar member 16' extends vertically above and below the fixed members 18' and 18a, the tubular portion as of the movable touch bar member is being provided with side openings 1% through which the fixed members 18' and 18a extend into the interior or" the tube 56. The ends of the tube 56' respectively above and below the fixed members 18 and 18a, are closed by plugs 53 and 63, which may be held in place by screws T432. The movable part 76' in which the socket 84' is formed slides within passage '74 in the plug 68 and has a trailing part '78 of reduced diameter which is slidably received within sleeve 3.454, the spring 82 being compressed between the sleeve 134 and the socket-carrying portion of the part 76.

The switches 12 are of a leaf-spring type, each com prising a fixed contact 32' carried by arm 1% and a movable contact 42 carried by flexible arm 1%. The arms 1% and 1% project from housing 111 which is secured to mounting flange 112; on the fixed members 13' and 18a respectively by means of screws 114. The re silient arm 1438 is normally biased upwardly so as to separate the contacts 32' and 42', and it carries at its end a body 11a? having a tapered recess 118 in the upper surface thereof into which the correspondingly tapered tip 124) of the extending part 96' of the connect'mg member 88 is received. Hence, as may best be seen from FIG. 7, when a given connecting element 88' rocks in response to lateral movement of its movable touch bar element 16, the interaction between its tapered tip 1% and the tapered recess 11.3 will cam the resilient arm 1533 toward the arm 1%, thus bringing the contacts 42' and 32 into engagement and closing the circuit through the switch 12'.

The switch actuating assemblies of the present invention will therefore cause the switches with which they are associated to close whenever pressure is exerted on any part of the exposed movable touch bar member 16 or 16' in an essentially lateral direction, and whether the movable touch bar element 16 or 16 bodily moves laterally while retaining its original upright position or tilts or pivots relative to the fixed members 18 or any one of them. The switch will therefore be actuated whether the touch bar is pushed or pulled in any direction and even if it is merely tilted. It will thus be effective to control the switches associated therewith for almost any manual manipuladon thereof except rotation about its longitudinal axis or attempted movement in the direction of its longitudinal axis. It may therefore be effectively and easily manipulated by heavily laden individuals or by individuals who are not properly indoct inatcd in the specialized mani ulations required with prior art devices. It provides a built-in safety feature, since if the doors tend to close on an individual, the impact of a door-carried touch bar 15 on that individual will be sufiicient to move the touch bar 16 and again actuate the switch controlled thereby and cause the doors to open.

These advantageous results are achieved by an essentially simple mechanical structure which is relatively foolproof, and which may be formed from a limited number of parts all of which may be readily and inexpensively manufactured to moderate dimensional tolerances. The moving parts are well protected against deleterious effects of external atmospheric influences such as moisture, dust or the like, particularly in the case of the embodiment of FIGS. 2-6. Many different types of switches may be employed, depending upon the nature of the electrical circuitry to be controlled. While two types of switches have been here disclosed, one for each of the illustrated embodiments, each type of switch can be used with either type of embodiment, and other types of switches could be substituted therefor. Many other variations may be 7 made inthe specific details of the structures here disclosed, all within the scope of the invention as defined in the following claims.

We claim:

1. A witch actuating assembly comprising a support having a pair of spaced fixed members, a movable member extending between said fixed members, means for mounting said movable member for rocking movement relative to said fixed members, a pair of connecting elements carried by said movable member, said connecting elements being movable with said movable member and rockable relative thereto, said fixed members each having a socket within which one of said connecting elements is rockably received, a switch carried by at least one of said fixed members, and means forming an operative connection between said switch and said connecting element received within the socket of said one of said fixed members for actuating said switch when said connecting element is rocked, means mounting one or" said connecting elements on said movable member for movement toward and away from the socket on the corresponding fixed member, and resilient means biasing said one connecting element toward said socket on the corresponding fixed member.

2. The assembly of claim 1, in which said socket in said one of said fixed members is formed in a wall having an aperture therethrough communicating with said socket, said switch being on the opposite side of said wall from said socket, the connecting element received in said socket having a part extending through said aperture, said switch actuating operative connection being betwen said switch and said connecting element part.

3. A switch actuating assembly comprising a support having a pair of spaced fixed members, a movable member extending between said fixed members, means for mounting said movable member for rocking movement relative to said fixed members, a pair of connecting elements carried by said movable member, said connecting elements being movable with said movable member and rockable relative thereto, said fixed members each having a socket within which one of said connecting elements is rockably received, a switch carried by at least one of said fixed members, and means forming an operative connection between said switch and said connecting element received within the socket of said one of said fixed members for actuating said switch when said connecting element is rocked, means mounting one of said connecting elements on said movable member for movement toward and away from the socket on the corresponding fixed member, and resilient means biasing said one connecting element toward said socket on the corresponding fixed member, said sockets tapering inwardly and terminating in essentially planar bottoms, the portions of said connecting elements engaging the bottoms of said sockets being essentially correspondingly planar.

4. The assembly of claim 3, in which said socket in said one of said fixed members is formed in a wall having an aperture theretldough communicating with said socket, said switch being on the opposite side of said wall from said socket, the connecting element received in said socket having a part extending through smd aperture, said switch actuating operative connection being between said switch and said connecting element part.

5. A switch actuating assembly comprising a support having a pair of spaced fixed members, a movable member extending between said fixed members, means for mounting said movable member for rocking movement relative to said fixed members, said fixed members each having a socket and said movable member having a pair of sockets registering respectively with said sockets in said fixed members, at least one of the sockets on one of said members having an aperture communicating therewith, a pair of connecting elements extending between said members and each received within a registering pair of sockets, at least one of said connecting elements having a part extending through said aperture, said elements being movable with said other of said members and, when thus moved, rocking in their respecti e sockets on said one of said members, at least one switch carried by said one or" said members, and means forming an operative connection between said connecting element part and said switch for actuating said switch when said connecting element having said part is rocked, one of said sockets being formed in a part which is movably mounted on the corresponding member so as to be movabl toward and away from the opposing socket on the other of said members, and resilient means biasing said one socket part toward said opposing socket.

6. A switch actuating assembly comprising a support having a pair of spaced fixed members, a movable member extending between said fixed members, means for mounting said movable member for rocking movement relative to said fixed members, said fixed members each having a socket and said movable member having a pair of sockets registering respectively with said sockets in said fixed members, at least one of the sockets on one of said members having an aperture communicating therewith, a pair or connecting elements extending bet een said members and each received withi 't registering pair of sockets, all of said sockets tapering inwardly and terminating in essentially planar bottoms, the portions of said connecting elements engaging the bottoms of said sockets being essentially correspondingly planar, at least one of said connecting elements having a part extending through said aperture, said elements being movable with said other of said members and, when thus moved, rocking in their respective sockets on said one or said members, at least one switch carried by said one of said members, and means forming an operative connection between said connecting element part and said switch for actuating said switch when said connecting element having said part is rocked, one of said sockets being formed in a part which is movably mounted on the corresponding member so as to be movable toward and away from the opposing socket on the other of said members, and resilient means biasing said one socket part toward said opposing socket.

7. The assembly of claim 1, in which said movable member is completely received between said fixed members.

8. The assembly of claim 1, in wln'ch said movable member is completely received between said fixed members, and a deformable sealing ring connected between said movable member and each of fixed members.

9. The assembly of claim 1, in which said movable member extends axially beyond said fixed members and has an opening in its side through which said fixed members extend into the interior thereof.

10. The assembly of claim 5, in which said movable part is carried by said movable member,

11. A switch actuating assembly comprising a fixed member, a movable member, means mounting said movable member for rocking movement relative to said fixed members, one of said members carrying a generally longitudinally extending connecting element, the other of said members having a socket within which said connect ing element is received, said connecting element mounted on said one of said members so as to be movable toward and away from the socket on said other of said members, resilient means biasing said connecting element toward said socket, a switch carried by said other of said members, and means forming an operative connection between said switch and said connecting element for actuating said switch when said element is rocked.

i2. The assembly of claim 11, in which said socket is essentially planar-bottomed, the portion of said connecting clement engaging the bot-tom of said socket being correspondingly essentially planar, whereby lateral relative movement of said members will cause sm'd connecting element to rock within said socket.

13. A switch actuating assembly comprising a fixed member, a movable member, means mounting said movable member for rocking movement relative to said fixed members, said members having registering sockets, one of said sockets being formed in a part which is movably mounted on the corresponding member s o as to be movable toward and away from the socket located on the other of said members, resilient means biasing said part toward said socket on the other of said members, a connecting element extending between said members, having first and second parts respectively seated in said sockets and having a third part extending therefrom, said element benig movable with said one of said members and, when thus moved, rocking in said socket on said other of said members, a switch carried by said other of said members, and means forming an operative connection between said 1% switch and said third connecting element part for actuating said switch when said element is rocked.

14. The assembly of claim 13, in which said sockets are essentially planar-bottomed, the portions of said connecting element engaging the bottoms of said sockets being correspondingly essentially planar, whereby lateral relative movement of said members will cause said connecting elements to rock Within at least one of said sockets.

Sorensen Sept. 5, 1950 Koch Sept. 30, 1952 

11. A SWITCH ACTUATING ASSEMBLY COMPRISING A FIXED MEMBER, A MOVABLE MEMBER, MEANS MOUNTING SAID MOVABLE MEMBER FOR ROCKING MOVEMENT RELATIVE TO SAID FIXED MEMBERS, ONE OF SAID MEMBERS CARRYING A GENERALLY LONGITUDINALLY EXTENDIN CONNECTING ELEMENT, THE OTHER OF SAID MEMBERS HAVING A SOCKET WITHIN WHICH SAID CONNECTING ELEMENT IS RECEIVED, SAID CONNECTING ELEMENT MOUNTED ON SAID ONE OF SAID MEMBERS SO AS TO BE MOVABLE TOWARD AND AWAY FROM THE SOCKET ON SAID OTHER OF SAID MEMBERS, RESILIENT MEANS BIASING SAID CONNECTING ELEMENT TOWARD SAID SOCKET, A SWITCH CARRIED BY SAID OTHER OF SAID MEMBERS, AND MEANS FORMING AN OPERATIVE CONNECTION BETWEEN SAID SWITCH AND SAID CONNECTING ELEMENT FOR ACTUATING SAID SWITCH WHEN SAID ELEMENT IS ROCKED. 